It all depends on team and driver preference. It is a simple matter to program the light sequence any way they desire. But these days the drivers do not use their eyes when it is time to shift, they receive a distinct beep in their ears. That way, for each gear the software knows best.

As blinky stated most driver use an audible beep/tone telling them when the optimal shift point is for the mode the engine is currently in. The shift lights have many different configurations that vary between drivers and manufacturers. The lights are there more as a redundancy feature incase the audible beep malfunctions